Presently fractures and diafissary pseudo-arthroses of femur, tibia and humerus are surgically treated by means of hollow or solid pins provided with a number of orifices or holes located along the longitudinal axis thereof. These are introduced within the marrow channel of the bones, and they are fastened thereto by means of screws or bolts passing freely through the pin orifices, and threaded on the bone cortical, thus forming the bone, pin and bolts into a sole assembly. The formation of a sole assembly assures the stability of the fracture or pseudoarthrosis for the necessary time to provide for the consolidation thereof, and such considerations fundamental to obtain adequate stability of the corresponding bone in order to have the corresponding bone joining.
In addition to fractures and diafissary pseudoarthroses which can be suitably treated with hollow or solid pins, it is also possible to treat osteothomy, tibia or femur shortenings or elongations with these same elements.
The treatment of fractures and the like by means of pins gives the patient the opportunity to carry out his or her normal activities after only a few days following the treatment, and this stimulates the bone joining and, therefore, the expeditous cure of the patient.
The main problem faced by the surgeon when using pins in the treatment of the above mentioned sufferings is to find the pin orifices during the operation, since the implant or pin is already inserted within the bone marrow channel, i. e., out of the sight of the surgeon. In order to solve this problem and to find the pin orifices, nearly all the present day techniques make use of an X-ray apparatus with an image-intensifier, looking that on the screen of this apparatus the images of the pin orifices are superposed to that of a positioner instrument, either of a manual type or constituted as an elongated slider to be affixed to the end of the pin or to the end of an impactor. The bit is introduced through the orifice of the instrument and thus the bone cortical is drilled until the pin orifice is reached. However, there are failures in this technique since it is easy for the bit to slide into the bone surface and, as a consequence thereof, the drilling may not register with the pin orifice.